Aquaculture CRSP 21st Annual Technical Report
Assessing Watershed Ponds for Aquaculture Development in Thai Nguyen, Vietnam
Tenth Work Plan, GIS: Planning, Policy, and Global Data Analysis Research 2 (10GISR2)
Dao Huy Giap and Yang Yi
Aquaculture and Aquatic Resources Management
Agricultural and Aquatic Systems and Engineering Program
School of Environment, Resources, and Development
Asian Institute of Technology
Nguyen Xuan Cuong and Le Thanh Luu
Research Institute for Aquaculture No.1
Dinh Bang, Tu Son, Bac Ninh Province, Vietnam
C. Kwei Lin and James S. Diana
School of Natural Resources and Environment
The University of Michigan
Ann Arbor, Michigan, USA
This study was conducted in the Dai Tu District of Thai Nguyen Province, Vietnam during November 2001 to January 2003. The purposes were to survey biophysical features, land and water uses, and socioeconomic conditions of watershed areas;
to develop a Geographic Information System (GIS) database for planning of aquaculture development; and to identify and estimate suitable watershed ponds for aquaculture. This study consisted of two components. The first included surveys and field measurements of soil and water quality in watershed ponds to assess the current state of these aquaculture systems, and the second was to develop a GIS database for identifying suitable watershed ponds for aquaculture using the collected data.
The survey showed that aquaculture was practiced in 82% (336 ha) of the existing watershed ponds in the study area. However, the fish production performance was poor in the watershed ponds, ranging from 0.3 to 3.6 t ha-1 y-1 with an average of
2.1 t ha-1 y-1, due mainly to inaccessibility of irrigation networks and lack of general aquaculture knowledge. Currently, aquaculture plays a small role in the Dai Tu District, contributing only 6.5% of household income. There is great potential for aquaculture development in watershed ponds by improving infrastructure and enhancing outreach and extension services.
The present study identified and quantified appropriate sites for watershed pond aquaculture in the Dai Tu District of Thai Nguyen using remote sensing and GIS and also identified the socioeconomic conditions in the study area. The primary data sources were three Systeme Pour l' observatoin de la Terre (SPOT) multi-spectral band satellite images for land-use change detection. Land-use types, roads, and hydrological systems were taken from topographic maps and updated with SPOT satellite imagery. Field surveys, digital topographic maps, land-use maps, and related information were used to identify suitable sites for watershed ponds to be used in aquaculture. Aquaculture production and economic returns from interviewed farmers were used to verify the results and comparisons among different land suitability levels. The developed GIS database predicted that about 4.7% (2,725 ha) of the total land area (57,618 ha) in Dai Tu District is suitable for watershed pond construction, compared to the existing 404 ha of watershed ponds. The present study has demonstrated the usefulness of the integration of remote sensing, GIS, and attribute data to select suitable sites for development of watershed ponds.
A large number of watershed ponds and reservoirs were created mostly for household water supply and crop irrigation in mountainous areas in central and northern Vietnam.
Occasionally, these ponds are also used for fish culture. Thai Nguyen Province, situated approximately 100 km north of Hanoi, is a population center serving as a gateway to northern Vietnam. The area possesses numerous small reservoirs and watershed ponds used for irrigating tea plantations,